Re: 9x42 conversion

You are not asking a easy question...Not enough info is given...For
instance are you going to use the acme screws, or get
ballscrews...What cutting speeds and rapids do you want...

Also, 1000 oz-in is only one number, probally holding torque...You
need the torque and rpm curve to know how much power you have for the
speed you want...Typically for steppers size nema 42 the torque drops
off sharply at 300 to 500 rpm or so...The curve is dependent on the
motor and the drive...usally a mfg publishes several curves for same
motor at different voltages to show how different drives will
perform...


Wally


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Polaraligned"
<polaraligned@o...> wrote:

>
>
> Thanks Wally. What I am looking for is the torque rating that is
> sufficient to drive a full size Bridgeport mill. Is 1000 oz-inch
> enough? should I go to a larger 1300 oz-inch?
> As for the driver, I heard that the Gecko's barely had enough
> current ability to handle driving motors on a large mill, plus
> they are not overcurrent protected. I just want to know what
> people out there are using sucessfully for Bridgeports. It is
> a much larger and capable machine than a import Mill/Drill.
> I will be using Mach 2 software.
>
> Thank You,
> Scott
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "cnc_4_me" <cnc4me@g...>
> wrote:
> >
> > Bridgport used nema 42 motors, and most people use this

size...But

> > some have successfuly used nema 34...It depends what you have
> access
> > to or have laying around, or how much you want to spend...and

what

> > kind of performance you want...
> >
> > Most people use a gecko stepper driver.
> >
> > http://www.geckodrive.com/
> >
> > they are adjustable up to 7 amps...The current you should use is
> > dependent on you motor...
> >
> > There is a gecko support group here...
> >
> > http://finance.groups.yahoo.com/group/geckodrive/
> >
> > The following is a general description of steppers to get your
> feet
> > wet...A few things you should know is steppers for the same frame
> > size can have very differnt torque and speed curves...In general

a

> > stepper with the lowest nameplate voltage and highest current

will

> > give you the best torque and speed...A 1.5v stepper is very good
> and
> > a 5v stepper is so so...
> >
> > Also note that the stepper is not driven by it nameplate
> > voltage...You typically run a stepper 20X its nameplate
> voltage...So
> > a 1.5v stepper is run at 30vdc...The gecko drives can be run up

to

> 7
> > amps and 80vdc...Gecko stepper drives need a external power

supply

> > you have to provide...
> >
> > I would suggest reading back in the archives in this group and
> geckos
> > at least 1 year to get a better handle on who, what were, when,
> and
> > why...I just got done doing the same...Lots of good stuff there,
> even
> > what software to use...
> >
> >
> > Wally
> >
> >
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Polaraligned"
> > <polaraligned@o...> wrote:
> > >
> > >
> > > Can anyone tell me what size steppers are the minimum required
> and
> > > also when looking for a stepper driver, what maximum current
> rating
> > > is needed to drive these steppers? The steppers will be

driving

> > the
> > > leadscrews with a 2:1 reduction via a belt drive.
> > >
> > > Thank you,
> > > Scott